Building

Native property search and valuation for homebuyers in Germany

Hypofriend Radar is Hypofriend's iOS and Android app for finding, comparing, and saving homes across Germany. It brings map-based discovery, detailed search filters, affordability signals, fair-price estimates, saved properties, and live updates into one bilingual mobile experience. I built and shipped the cross-platform product with Vue 3, TypeScript, Capacitor, MapLibre, Pusher, Amplitude, and Sentry, including the native release pipelines for both stores.

AI support chat that lifted lead conversion by 35%

An AI support chat across Hypofriend's products, which help people in Germany finance and buy their homes. I designed and shipped it end to end: SSE streaming over an in-house mortgage and investment LLM, desktop and mobile widgets plus a full chat page, progressive token rendering and resumable history. Context-aware system prompts per product touchpoint (affordability, mortgage offer, exposé) and a CTA auto-send compose prompts from live property and user data. I then extracted the chat engine into @hypofriend/hf-chat, a standalone Vue 3 package used by Hypofriend, PensionFriend and InvestFriend. The chat lifted lead conversion by 35% and contributed to a 5% month-on-month rise in property purchases.

PragVue 2026 hackathon winner: AI support ticketing

Our team's winning project at the PragVue 2026 hackathon (1st place). Users describe a support issue in their own words, search their requests and follow updates through to resolution, and the demo also opens on a phone through a QR code. Claude (Anthropic API) turns what a user types or says into a structured request and sums up each ticket's updates in plain language, with voice input through the browser's speech recognition. We used Claude Code to plan, build and test the app. I helped build it with the team and presented the live demo.

Open-source harness that stress-tests conversational AI agents

An adversarial simulation and evaluation harness for conversational AI agents. It spins up difficult customer personas (angry escalators, prompt injectors, policy probers), runs them against a target agent in parallel, and grades each transcript with deterministic decision-tree judges for task completion, tone and policy, and groundedness against the target's own documents. Built on LangGraph for parallel multi-agent orchestration and LangChain for the model layer, with a small RAG pipeline that catches hallucinated prices and policies, and a self-contained HTML report that draws each judge's decision path. TypeScript, tested with Vitest, with 1,200+ npm downloads since its June 2026 release.

Open-source authorization and proof layer for AI agent actions

An authorization, proof, and audit layer for what AI agents actually do. A policy decides which tool calls run freely, which are blocked, and which need a person to sign off. On approval, PermitRail issues a short-lived Ed25519-signed proof bound to the exact action, the tool runs once, and a signed receipt lands in the audit log. Zero runtime dependencies, runs on Node, browsers, and edge runtimes, and ships a runnable MCP server.

AI voice agents for businesses that live on the phone

Linga is a multi-vertical AI voice platform. It answers a business's calls 24/7 in natural speech, captures the request as a structured lead, and delivers it to the owner the moment the call ends. One engine, tuned per industry through a playbook (prompt, capture fields, voice, guardrails): Linga for Cargo and Linga for Auto Dealers are live, with hotels, restaurants, and real estate next. Built on a managed real-time voice stack with per-vertical playbooks, anti-hallucination guardrails, and WhatsApp and email lead delivery.

AI Document Understanding for European Residents

Upload any official document - government letters, tax notices, contracts - and get a clear explanation in your language with deadlines, action items, and reply drafts. Supports 8 countries and 21 languages.

AI-Powered Language Learning Platform

Adaptive German language learning with AI speaking practice, spaced repetition, TELC exam prep, and structured daily sessions. Tracks progress across all language skills.

EUDI Wallet Verification API for Developers

A developer-first API that lets any app integrate EU Digital Identity Wallet verification. Supports age checks, identity verification, and residency - all compliant with eIDAS 2.0 and OpenID4VP.

Global design system for ArtNight's booking and host platforms

ArtNight runs guided painting and creative events every day in 60+ cities across Germany and Austria, with more than a million participants to date. On the Napcore team I led a team of four on the global design system, bringing consistency and accessibility to the customer booking experience and the event platform used by 30K+ hosts. I built reusable, accessible components, aligned UI patterns across platforms, and set up unit testing for the legacy codebase, raising coverage from 0 to 56% in my first three months. The work fed into the Vue 2/Nuxt 2 to Vue 3/Nuxt 3 upgrade (Vuex to Pinia, Jest to Vitest).

Data-compliance platform, acquired by Privitar

Kormoon.ai helps businesses meet their data-compliance obligations while keeping their data secure. Through One World Coders, I led a three-person team that delivered the final features of the application and got it stable and ready to launch, working across a React and Redux frontend, a Ruby on Rails backend, and Auth0 for authentication. Privitar acquired Kormoon while I was still on the project, and Kormoon is now part of Salesforce through Informatica.